ee
3
246
IRON-55 IN RONGELAP PEOPLE, FISH AND SOILS
Disintegration rates of 55Fe in the samples were
determined by comparison with 55Fe electro-
March 1970, and Fig. 1 shows a frequency
distribution of the body burdens of males and
females. The Rongelapese which were included
deposited from a standard solution obtained
from the National Bureau of Standards.
Correction was made for the self-absorption of
the X-rays in the electrodeposited iron. Stable
iron was determined colorimetrically, using o-
in this study consisted entirely of those individuals who were subjected to external radiation
in 1954. Iron-55 levels in the blood samples
were sufficiently high to permit count rate
measurements to +5°%at the 95% (20) confidence level. Not all donors were weighed in
26 ml). Total blood volume was estimated
using body weight and average blood volumes
of 82 ml blood per kg body weight for males
were used to compute total blood volumes.
However, weights from previous years applied
mostly to younger donors. Since weight gener-~
phenanthroline as the color-forming agent.10
Body burdens were estimated byfirst measuring the 55Fe in a known volume of blood (4—
1970, therefore body weights from previous years
ally increases with age, some individual estimates of 55Fe body burdens, and therefore the
averages shown in Table 1, are likely to be
and 74 ml blood per kg body weightfor females.
The iron content of blood was assumed to be
65% of the total body iron. This method of
calculating total blood volume is that used by
Persson"?) in his estimate of 55Fe body burdens
in Lapps of Northern Sweden. Previousestimates of body burdens from composite blood
specimens"™-5) were made assuming that the
conservative.
The maximum body burden in the males
was 0.85 wCi, while 3 females had body burdens
greater than this value. The maximum ob-
served female body burden was
average total blood volume was 51. and that
1.0 4Ci,
60 % of thetotal iron is in the blood. Usingthis
method with the Rongelap data, the average
Table 1. Average Fe body burdens of Rongelapese
calculated using body weights.
sampled
58Fe body burdens agreed within 15% of those
Date
-
March 1970
RESULTS AND DISCUSSION
104
MALES
»
(xCi)
0.43 + 0.17
32/F
0.40 + 0.27
* Standard error (1c) of the mean.
J
94
28/M
March 1970
Table 1 gives the average body burdens of
53Fe in the group of Rongelapese sampled in
55F
.
No. of subjects/sex
FEMALES
»
,
a
~
a
§ 5
4
Nn 44
4
$*
]
14
4
a
3
24
O-
Qo
0.20
040
O60
+e
O08
0
020
S5Fe body burdens (uCi)
040
9060
0.80
:
>0.90
Fic. 1. Frequency distribution of °5Fe body burdens in Rongelap
males and females.
Body burdens have been grouped into classes,
Example: 3 Rongelap males had 5*Fe body burdens between 0.10~0.20
pCi while nine females had “Fe body burdens in the same activity
interval.
aT